U.S. Pat. No. 4,090,378 shows a machine operative on a shoe assembly comprising a last having an insole located on its bottom on an upper mounted thereon with the margin of the upper secured to the bottom of the insole so that the upper margin and the insole form the bottom of the shoe assembly, the machine functioning to rough the upper margin. The shoe assembly bottom has spaced substantially planar end portions consisting of a heel seat portion and a forepart portion and a substantially planar shank portion between the two end portions, the three planar portions lying in different planes. The machine comprises: a support, for supporting the shoe assembly bottom-up, mounted for rocking movement through an upwardly concave arc; a roughing tool located above the shoe assembly; means for yieldably urging the roughing tool downwardly against the shoe assembly; and means for so moving the shoe assembly and means for so adjusting the position of the roughing tool that the upper margin from one end of the shoe assembly bottom to the other end of the shoe assembly bottom moves past the roughing tool and is roughed by the roughing tool with a first end portion, the shank portion, and the second end portion of the shoe assembly bottom moving past the roughing tool.
In the machine of U.S. Pat. No. 4,090,378, the shoe assembly support is initially rotated 180 degrees about a vertical axis to rotate a first end of the upper margin past the roughing tool, is then moved horizontally and linearly to move a side of the upper margin past the roughing tool, and is then again rotated 180 degrees about the vertical axis to rotate the second end of the upper margin past the roughing tool. During the linear horizontal movement, the shoe assembly support maintains the first end of the shoe assembly in a horizontal plane. During the horizontal linear movement of the shoe assembly support, the shoe assembly is so rocked through the upwardly concave arc that the second end of the shoe assembly lies in a horizontal plane during its rotation. The purpose of maintaining the two end portions of the shoe assembly in horizontal planes during their rotations is to ensure that the roughing tool engages the upper margin uniform distances inwardly of the outer periphery of the upper margin.
Due to the multi-planar construction of the shoe assembly bottom, portions of the shoe assembly bottom are sloping upwardly as they move past the roughing tool and other portions of the shoe assembly bottom are sloping downwardly as they move past the roughing tool. It is desirable that the upper margin be moved past the roughing tool at a uniform speed in order for the roughing tool to effect uniform roughing on the upper margin. However, with the roughing tool being yeildably urged downwardly against the upper margin, the passage of an upwardly sloped margin portion past the roughing tool tends to slow the movement of the upwardly sloped margin portion past the roughing tool and the passage of a downwardly sloped margin portion past the roughing tool tends to increase the rate of movement of the downwardly sloped margin portion past the roughing tool.